Changing exposure

If you use Av, you set the aperture and the camera sets the shutter speed to match. To achieve a long exposure all you need to do is set a small (large number such as f/16) aperture and you'll see what setting the camera will use in the viewfinder display.

Alternatively, use manual and set what you want, but you will have to watch the exposure display to make sure the exposure is correct. Just centre the readout by changing aperture, shutter speed or both.

The exposure time might not change if you use auto-iso because you leave it up to the camera to decide what to change and by how much.

When working in an 'automatic exposure' mode such as Av, TV, Tav, Sv, the process to adjust exposure is 'exposure compensation', which forces the camera to change the exposure value (ev) by adjusting the variable parameter and while holding the 'priority' parameter ....eg in TV mode then 'time value' is the priority parameter, and aperture would be varied to force the exposure change.

Maria, you said you wanted to change the 'exposure time' ,so I'm guessing you wanted to have a slower shutter speed for a movement effect. I suppose if you needed to do this but wanted an automatic exposure, then TV is the mode to choose. As you lengthen the time value then to compensate the aperture would get smaller and smaller, keeping the brightness the same.

I agree with the others here who have referred to manual as the most versatile mode, but as said you need to keep a close eye on the exposure variation scale along the bottom of the viewfinder to be sure you don't get too far away from your intended brightness.

Thanks Nigel, i understand this but i think what i was hoping for was a way of adjusting these setting myself without them going on auto, i was just hoping for the best of both worlds, i'll try manual again and hope the exposure variation will be kind to me, many thanks

Hi Maria

My suggestion would be to set the camera to AV mode, get the aperture set as you want it and do a test shot to judge where the exposure / shutter speed needs to be. Once you've done this to give a guideline, it's easy to switch the camera to manual and tweak it from there.

I use this method a lot, but also use the exposure compensation mentioned by Nigel, almost always I will be in AV mode when doing this.

I've put a very simple little shot on the Gallery today that uses the exposure compensation in AV mode, this one was under-exposed by just over 2 stops to make the background dark.

Best wishes
David

Hi Maria,

I use TAV mode but restrict the allowed ISO range to suit, easily done from the info screen. I consider what i'm doing and set shutter and aperture accordingly. I find that a nice compromise between semi auto and full manual which of course you can also use and use the plus/minus meter from the viewfinder and top LCD display

Hi Maria, in full manual you should be able to set exactly what you want i.e. narrow aperture , slow shutter, with nothing changing but depending on what you are trying to achieve with the slow shutter speed you may also need to attach an ND filter to the lens to get the speed slow enough

Can't you use the exposure adjustment to influence Av mode for example?

I use this when then metering is not correct for my subject. Such as a bird against a bright sky, where the metering will be based on the big bright area and not the bird.

Maria, maybe you will have to resort to ND filters if you require very long exposures.

Others will comment, but looking back up I see you have a k-5 camera. Something looks to have changed between that series and the k-30 that I have.

In my k-30 I can select a fixed ISO value in all the modes you list, or I can select a band from which the camera is allowed to pick from. This came up recently but it appears that behaviour is different n the more modern camera bodies.

Apologies for not checking the model earlier. In tapping this reply out on a cell phone. Bottom line is I can, but I'm not sure about your camera sorry.